The present invention relates generally to superconductivity, and more particularly to supporting a superconductive coil in a superconducting device.
Superconducting devices include, but are not limited to, superconducting rotors for synchronous electrical machines, such as generators and motors, and superconducting magnets for MRI (magnetic resonance imaging) machines, maglev (magnetic levitation) transportation systems, magnetic energy storage devices, and linear motors. The superconductive coil or coils in a superconducting device are made from a superconducting material, such as niobium-tin, requiring a temperature at or below a critical temperature to achieve and maintain superconductivity. Cooling techniques include cooling an epoxy-impregnated coil through a solid conduction path from a cryocooler or through cooling tubes containing a liquid and/or gaseous cryogen and cooling a porous coil by immersion in a liquid and/or gaseous cryogen. The superconductive coil typically is surrounded by a vacuum enclosure. In a particular application, a thermal shield may be added between the superconductive coil and the vacuum enclosure.
Applicants are aware of techniques for supporting the superconductive coil in the superconducting device which include using racetrack-shaped, uni-directional filamentary-reinforced-epoxy (FRE) suspension straps between mounting pins connected to the superconductive coil and the thermal shield and between mounting pins connected to the thermal shield and the vacuum enclosure. Such straps can be costly and require complex mounting pin or other hardware to support and transmit the coil loads evenly, especially in the case of rotating coils, such as those in a superconducting rotor where centrifugal loading on the coils can be substantial. What is needed is a superconducting device having an improved support structure for its superconductive coil or coils.